t = actual date, copyright
date
m = multiple dates from/to
n = unknown
p = issue date/recording
date1 when there is a
difference
q = questionable (such as 1982 or 3)
r = reissue date/original
date2
s = single date (such as 1982, [198-], etc.)
See also Dates on sound
recordings1Issue date/recording date:
When there is a span of recording dates, the earliest date of recording
goes in date 2.2Reissue date/original date:
A sound recording is considered a reissue when it is issued with a new
manufacturer number, issued on a new label or in a new format, or when it
is a collection with previously released material from numerous
sources.

eng = English
fre = French
ger = German
ita = Italian
rus = Russian
spa = Spanish
zxx = no linguistic content
und = undetermined language or arbitrary syllables, humming, or other
human-produced sounds for which a language cannot be specifiedMultilingual items:
For two to six languages use:
° the predominant language code
° the code that is first alphabetically if predominance
cannot be determined.
For six or more languages use:
° the code for the language of the first title .
° code "mul" if there
is no predominant language and the cataloging institution has chosen not
to specify a language.
See US
MARC language list for a full list